Description:
A vulnerability was reported in Xen. A local user on the guest system can gain elevated privileges on the host system.

A local user on a PV guest system can exploit a validation flaw in the PV superpage functionality HYPERVISOR_mmuext_op hypercall (MMUEXT_MARK_SUPER and MMUEXT_UNMARK_SUPER sub-ops) and page table updates to obtain information, deny service, or gain elevated privileges on the host system.

Th PV superpage feature is disabled by default.

x86 systems are affected.

Qinghao Tang of 360 Marvel Team reported this vulnerability.

Impact:
A local user on the guest system can obtain information, cause denial of service conditions, or gain elevated privileges on the host system.

Solution:
The vendor has issued a fix (xsa167-4.4.patch, xsa167-4.6.patch, and xsa167.patch).